docs: def get_channel_access(self, channel=None, read_mode='volatile'):
          """Get channel access
  
          :param channel: number [1:7]
          :param read_mode:
          non_volatile  = get non-volatile Channel Access
          volatile      = get present volatile (active) setting of Channel Access
  
          :return: A Python dict with the following keys/values:
            {
              - alerting:
              - per_msg_auth:
              - user_level_auth:
              - access_mode:{
                  0: 'disabled',
                  1: 'pre_boot',
                  2: 'always',
                  3: 'shared'
                }
              - privilege_level: {
                  1: 'callback',
                  2: 'user',
                  3: 'operator',
                  4: 'administrator',
                  5: 'proprietary',
                }
             }
          """
          if channel is None:
              channel = self.get_network_channel()
          data = []
          data.append(channel & 0b00001111)
          b = 0
          read_modes = {
              'non_volatile': 1,
              'volatile': 2,
          }
          b |= (read_modes[read_mode] << 6) & 0b11000000
          data.append(b)
  
          response = self.raw_command(netfn=0x06, command=0x41, data=data)
          if 'error' in response:
              raise Exception(response['error'])
  
          data = response['data']
          if len(data) != 2:
              raise Exception('expecting 2 data bytes')
  
          r = {}
          r['alerting'] = data[0] & 0b10000000 > 0
          r['per_msg_auth'] = data[0] & 0b01000000 > 0
          r['user_level_auth'] = data[0] & 0b00100000 > 0
          access_modes = {
              0: 'disabled',
              1: 'pre_boot',
              2: 'always',
              3: 'shared'
          }
          r['access_mode'] = access_modes[data[0] & 0b00000011]
          privilege_levels = {
              0: 'reserved',
              1: 'callback',
              2: 'user',
              3: 'operator',
              4: 'administrator',
              5: 'proprietary',
              # 0x0F: 'no_access'
          }
          r['privilege_level'] = privilege_levels[data[1] & 0b00001111]
          return r